Thread-Forming Fastener Tip Angle for Controlled Workpiece Heating
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Solution Overview
Problem
Existing thread forming fasteners face issues with under-heating or overheating of the workpiece during insertion, leading to sub-optimal joint quality, including separation of layers and inadequate engagement between threads and workpiece material.
Innovation Solution
A fastener design with a tapered tip angle of at least 50 degrees and a shank section that allows controlled heating and threading, reducing the likelihood of under-heating or overheating by optimizing contact area and material deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the fastener uses a conventional tip angle (less than 50 degrees), then the insertion force is reduced, but the workpiece is under-heated leading to sub-optimal joint quality and layer separation
Solution Approach 1:
The patent changes the geometric parameter of the tip angle from conventional values (less than 50 degrees) to at least 50 degrees. This parameter change increases the contact area between the fastener tip and workpiece surface, thereby increasing the heat generation during rotation and ensuring adequate heating of the workpiece for optimal joint quality.
Solution Approach 2:
The patent applies a specific tip angle of at least 50 degrees locally at the tip section of the fastener. This local geometric feature is designed to optimize the contact area with the workpiece surface during insertion, ensuring sufficient heat generation at the critical insertion zone without affecting other parts of the fastener.
2Temperature
If the fastener rotates at high speed to heat the workpiece, then the heating efficiency is improved, but the workpiece may become overheated causing material degradation and poor thread engagement
Solution Approach 1:
The patent employs dynamic control of the insertion process where the fastener is rotated during insertion to generate heat, and the rotation continues while the fastener is being threaded into the workpiece. This dynamic approach allows controlled heating followed by immediate threading, ensuring the workpiece is heated to the optimal temperature range without excessive overheating that would degrade the material.
Solution Approach 2:
The patent maintains continuous rotation of the fastener throughout the insertion process - both during the initial heating phase and while threading into the workpiece. This continuous rotational action ensures consistent heat generation and material deformation, preventing temperature fluctuations that could lead to overheating or under-heating.
3Temperature
If the tip section has a large contact area with the workpiece, then the heat generation is improved, but the insertion force required increases
Solution Approach 1:
The patent optimizes the tip angle parameter to at least 50 degrees, which provides an optimal balance between contact area and insertion force. This specific angular parameter generates sufficient heat through increased contact area while maintaining manageable insertion forces, unlike flatter tips that would generate more heat but require excessive force.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The fastener design improves joint quality by minimizing separation and gapping, ensuring effective engagement between threads and workpiece material, resulting in a more robust and reliable connection.
Implementation Method 1
the fastener is rotated while in contact with the workpiece such that the workpiece is heated
Data Source
AI summary
There is disclosed a hole forming and thread forming fastener (2). The hole forming and thread forming fastener (2) comprises a head (4) and a shank (10) that defines a longitudinal axis (L). The shank (10) comprises a shank section (12) and a tip section (14). The shank section (12) extends from the head (4). The tip section (14) extends from the shank section (12) and is opposed to the head (4). At least part of the shank section (12) is threaded. The tip section (14) is at least partially tapered and defines a tip angle (α). The tip angle (α) is at least 50 degrees.